Unlike other recent acquisitions in technology, this one doesn't immediately make sense.

When Facebook bought Instagram for $1 billion, it was a perfect fit. Facebook is all about photo sharing. Instagram was eating into Facebook's business as the primary social network for sharing photos.

When Facebook bought WhatsApp for $19 billion, it was getting a messaging service that was on pace to have 1 billion users. WhatsApp was a social network of its own, and as such it posed a threat to Facebook, which has its own messaging service.

But Oculus Rift? It's not a social platform. It is no threat to Facebook in the near term, and probably not in the long term.

So why did Facebook buy the company? There are two, intertwined reasons to explain this deal.

The first and most straightforward explanation is just what Facebook CEO Mark Zuckerberg said last night. He believes virtual reality could be the next major computing platform. First there was desktop computer, then there was mobile, and he believes virtual reality is next.

"We're going to make Oculus a platform for many other experiences," said Zuckerberg while announcing the deal. "Imagine enjoying a courtside seat at a game, studying in a classroom of students and teachers all over the world or consulting with a doctor face-to-face — just by putting on goggles in your home. This is really a new communication platform."

Some people are skeptical about Zuckerberg's vision. In general, people don't like to wear goggles or glasses in their homes. It's one of the reasons 3-D televisions have never taken off. The immersive experience of an Oculus is mind-blowing, according to pretty much anyone who's tried it, but it's also isolating, which could limit its mainstream appeal.

But if Zuckerberg is wrong — and Oculus is not the next major platform — it's not a big deal.

Sure, $2 billion makes it sound like a big deal, but the deal terms are good for Facebook. It is spending $400 million in cash and using 23.1 million shares to buy Oculus. There's an additional $300 million in earnout bonuses.

This is the second reason for Zuckerberg buying Oculus. Zuckerberg looks at his stock price, which is quite high right now and thinks, "Great! I can spend this buying cool stuff!"

Facebook had $11.45 billion in cash at the end of last year. It spent $4 billion in cash on WhatsApp. Spending a further $400 million of the cash on a company that might be pioneering the next major computing platform is a no-brainer — it's loose change.

As for spending stock, it's basically monopoly money to Zuckerberg right now. Facebook won't be judged on the performance of Oculus for three years, at least. For now, it's all about the success of the core business, Instagram, and, to a lesser extent, WhatsApp.

Besides, investors are rewarding technology companies for aggressively investing in the future. Facebook's stock hit a high in the days following its WhatsApp acquisition. (Normally, acquiring companies see their stock go down as they lose cash.) Google has been on a tear as it announces all sorts of technology experiments. Amazon has been rewarded for pursuing investment over profits.

By contrast, Apple's shares have been pretty lifeless as it works behind closed doors on whatever its developing.

(And, by the way, Facebook's stock is flat in pre-market trading.)

Zuckerberg looks at this landscape and figures, why not spend some of Facebook's equity?

Is there a downside to this deal? Not really. If Oculus turns out to be a bust, then Zuckerberg is mostly just embarrassed for getting it wrong.

It's not going to sink Facebook, and Zuckerberg spent only $400 million in cash. If Oculus turns out to be a good gaming platform, like Xbox, but not a major computing platform, that's not the end of the world either. Xbox is a strong business on its own.

If Zuckerberg is right, he bought the next iPhone-like product for just $4oo million in cash.